JPS5930237A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which is superior in electromagnetic characteristic, durability, wear resistance, antistatic characteristic, etc., hard to stain a magnetic head, guide pin, etc., and suitable for video, by incorporating TiO which has specific mean grain size in magnetic alloy powder within a specific rate range. CONSTITUTION:The magnetic alloy powder contains 0.1-20wt% TiO with 0.01- 5mum mean grain size and a base film is coated with the powder by using a resin binder, and heated to cure the resin binder, obtaining a magnetic tape. Since TiO has 5-6 Moh's hardness and is conductive, the magnetic tape for a video tape recorder which is superior in antistatic characteristic, wear resistance, electromagnetic conversion characteristic, and running characteristic and a still time extension, and is hard to stick dust and dirt is obtained.

Description

Detailed Description of the Invention Gold magnetic powder and alloy magnetic powder of 0.1 to 20
By containing at least titanium monoxide with an average particle size of 0.01 to 5 μm by weight, it has excellent magnetostatic properties, running properties, durability, and abrasion resistance, and also has an excellent antistatic effect. It is an object of the present invention to provide a magnetic recording medium that has extremely little screen fluctuation during recording and reproduction, since dirt may occur on the magnetic head, guide pins, etc. of a recording and reproduction device during long-time running.

- Magnetic recording media for video tape recorders travel while making intense contact with magnetic heads, guide pins, etc. during recording and playback, so the magnetic layer coating is likely to wear out, so a material with excellent wear resistance is required. ing. There is also a need for measures to prevent static electricity from accumulating, which causes running problems when the vehicle is repeatedly driven.

Also, as home video tape recorders became more popular, small portable ones were developed, and video tape recorders with built-in cameras were developed, and alloy magnetic powder with high coercive force was used to improve recording density. The magnetic tape used is being developed.

In such magnetic tapes, attempts have been made to include alumina, carborundum, chromium oxide, titanium dioxide, etc. in the magnetic layer from the viewpoint of the above-mentioned wear resistance.

However, these additives have problems such as excessive wear on the magnetic head, reduce the packing density of the magnetic powder, and also require the inclusion of carbon black or the like as an antistatic measure. , which is not necessarily satisfactory.

As a result of various studies conducted by the present inventors in order to eliminate the above-mentioned drawbacks, the present inventor used an alloy magnetic powder as the magnetic powder in the magnetic layer of a magnetic recording medium, and found that the alloy magnetic powder has a weight of 1 to 20
It has been discovered that an ideal magnetic recording medium can be obtained by including at least a magnetic layer with titanium monoxide having an average particle size of 0.01 to 5 μm, preferably 0.05 to 1 μm, at a ratio of 1%. It is.

The titanium monoxide used here is a gray or black fine powder with moderate hardness (Mohs hardness 5 to 6).
Furthermore, it has been found that it has electrical conductivity and is more effective for alloy magnetic powder than for oxide-based magnetic powder as the magnetic powder contained in the magnetic layer.

Hereinafter, some specific examples of the magnetic recording medium according to the present invention will be described.

Example 1 100 parts by weight of 1 alloy magnetic powder, 10 parts by weight of vinyl chloride-vinyl acetate-vinyl alcohol copolymer, 10 parts by weight of polyurethane elastomer, 1 part by weight of silica/tin, mixed solvent of toluene, methyl ethyl ketone and methyl ibutyl ketone. A mixture of 300 parts by weight and 5 parts by weight of titanium monoxide with an average particle size of 0.05 μrn was mixed and dispersed in a sand mill for about 20 hours, 5 parts by weight of polyisocyanate was added to this, and this magnetic paint (carbon black not included) was prepared. For example, it is applied to a polyester film having a thickness of 14.5 μm to a predetermined thickness, and then calendered after drying. Then, add this to about 6
After holding at 0'C for 24 hours to effect a curing reaction, the tape is slit into a width of, for example, 10 inches to obtain a magnetic tape for, for example, a video tape recorder.

Example 2 A magnetic tape is obtained in the same manner as in Example 1 except that the amount of titanium oxide added is 10 parts by weight.

Example 3 A magnetic tape is obtained in the same manner as in Example 1 using titanium monoxide having an average particle size of 0.2 μm.

Comparative Examples 1 to 3 M20hCi203 instead of titanium monoxide in Example 1,
.

Alternatively, a magnetic tape is obtained in the same manner as in Example 1 using r102.

The magnetostatic properties (Bl-, Gauss, measured magnetic field 5 visits) of the magnetic tapes obtained as described above were determined to be 3010 for Example 1 and 287 for Example 2.
0, 3050 in Example 3, 2890 in Comparative Example 1, 2910 in Comparative Example 2, and 2820 in Comparative Example 3. Comparing those of Examples 1 and 3 with those of Comparative Examples 1 to 3, it is found that the magnetic tape of this example has improved by 100 to 230 Gauss. Wear resistance is determined by the increasing tendency of the coefficient of dynamic friction when the rotary drum is pressed against the drum and rotated at 200°C (a guideline for still playback characteristics)
Examination of the results shows that all of the magnetic recording media of the present invention are excellent, while those of Comparative Example 1 are extremely poor, and those of Comparative Examples 2 and 3 are poor. It has excellent wear resistance and has a long still playback time.

Furthermore, when the above-mentioned magnetic tape is mounted on a recording/reproducing device and run, static electricity is generated due to the sliding contact with the magnetic head, etc., and this charged static electricity causes dirt and dust to adhere, reducing running performance. As a guide to the characteristics that will cause
When the surface resistivity (,2/sq,) was measured, the one in Example 1 was 1.2X 108, and the one in Example 2 was 9.
0X10', that of Example 3 is 8.5X1.08, whereas that of Comparative Example 1 is 4. OX] 010, Comparative Example 2 is 1.6X109, Comparative Example 3 is 3.2
XiO9, the magnetic recording medium of the present invention has an excellent antistatic effect, and is difficult to attract dirt and dust.
It also has good running properties without degrading electromagnetic conversion characteristics.

As described above, the magnetic recording medium according to the present invention has an average grain size of 0.00000 in the magnetic layer. It contains at least titanium monoxide of ~5 μm and alloy magnetic powder, and the content ratio of titanium oxide is within the range of 01 to 20% by weight based on the alloy magnetic powder, so that the magnetostatic properties, running properties, It is a magnetic recording medium with excellent wear resistance, durability, and antistatic effect.For example, the magnetic head of a recording/playback device is less likely to get dirty when running for a long time, and there is extremely little screen fluctuation during recording and playback. It has characteristics.

Patent applicant: Victor Japan Co., Ltd.

Claims (1)

[Claims] The magnetic layer contains at least titanium monoxide and alloy magnetic powder with an average particle size of 0.01 to 5 μm, and the content of titanium oxide is within the range of 0.1 to 20% by weight based on the alloy magnetic powder. A magnetic recording medium characterized by: